Alert archive / Tennessee / Mesoscale Discussions in 2013

Mesoscale Discussion 755

May 21, 20134 states

The Storm Prediction Center issued this mesoscale discussion at May 21, 2013, 2:42 PM CDT for 4 states. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued
May 21, 2013, 2:42 PM CDT (19:42 UTC)
Expired
May 21, 2013, 3:45 PM CDT
In force
63 min
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 54 counties

Clay County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Greene County, AR, Jackson County, AR, Lawrence County, AR, Lee County, AR, Mississippi County, AR, Monroe County, AR, Phillips County, AR, Poinsett County, AR, St. Francis County, AR, Woodruff County, AR, Dunklin County, MO, Pemiscot County, MO, Alcorn County, MS, Benton County, MS, Calhoun County, MS, Coahoma County, MS, DeSoto County, MS, Lafayette County, MS, Lee County, MS, Marshall County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Tate County, MS, Tippah County, MS, Tishomingo County, MS, Tunica County, MS, Union County, MS, Yalobusha County, MS, Benton County, TN, Carroll County, TN, Chester County, TN, Crockett County, TN, Decatur County, TN, Dyer County, TN, Fayette County, TN, Gibson County, TN, Hardeman County, TN, Hardin County, TN, Haywood County, TN, Henderson County, TN, Lake County, TN, Lauderdale County, TN, Madison County, TN, McNairy County, TN, Obion County, TN, Shelby County, TN, Tipton County, TN, Weakley County, TN

The radar

The Memphis radar (KNQA), 22 km from the middle of the area, began a volume at 19:46 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Little Rock, AR (KLZK), launched 12:00Z, 7.7 hours before the alert went out and 39 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Little Rock, AR at 12:00Z on 2013-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 35 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Little Rock, AR at 12:00Z on 2013-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
35 J/kg
Mixed-layer CIN
-268 J/kg
Mixed-layer LCL
1441 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
106 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 20, 7:39 PM CDTTornado WatchSPCBaxter, Benton, Boone, Carroll, Cleburne, Conway and 26 more6 hr
May 21, 12:03 AM CDTSevere Thunderstorm WatchSPCCrawford, Franklin, Sebastian7 hr
May 21, 12:50 AM CDTSevere Thunderstorm WatchSPCClay, Craighead, Crittenden, Cross, Greene, Lawrence and 5 more3 hr
May 21, 4:20 AM CDTMesoscale DiscussionSPCCrawford, Franklin, Sebastian55 min
May 21, 7:47 AM CDTMesoscale DiscussionSPCCrittenden, Cross, Lee, Mississippi, Phillips, Poinsett and 1 more58 min
May 21, 1:35 PM CDTMesoscale DiscussionSPCLafayette, Miller115 min
May 21, 1:50 PM CDTTornado WatchSPCBradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 13 more8 hr
May 21, 3:00 PM CDTTornado WatchSPCArkansas, Ashley, Chicot, Clay, Craighead, Crittenden and 11 more7 hr
May 21, 3:18 PM CDTMesoscale DiscussionSPCBradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 11 more87 min
May 21, 5:54 PM CDTMesoscale DiscussionSPCCalhoun, Columbia, Hempstead, Lafayette, Miller, Nevada and 2 more66 min
May 21, 6:23 PM CDTMesoscale DiscussionSPCChicot, Desha67 min
May 20, 8:07 PM CDTMesoscale DiscussionSPCAudrain, Callaway, Christian, Cole, Douglas, Gasconade and 15 more23 min
May 20, 8:53 PM CDTMesoscale DiscussionSPCAudrain, Franklin, Gasconade, Jefferson, Lewis, Lincoln and 10 more67 min
May 20, 10:25 PM CDTMesoscale DiscussionSPCBollinger, Butler, Cape Girardeau, Mississippi, New Madrid, Pemiscot and 5 more65 min
May 20, 10:56 PM CDTTornado WatchSPCBollinger, Butler, Cape Girardeau, Carter, Mississippi, New Madrid and 5 more6 hr
May 21, 2:59 AM CDTMesoscale DiscussionSPCMississippi, Scott91 min
May 21, 11:27 AM CDTMesoscale DiscussionSPCBedford, Bledsoe, Cannon, Cheatham, Clay, Coffee and 39 more63 min
May 21, 2:12 PM CDTMesoscale DiscussionSPCAnderson, Bledsoe, Campbell, Claiborne, Clay, Cumberland and 15 more63 min
May 21, 2:26 PM CDTSevere Thunderstorm WatchSPCAnderson, Bledsoe, Blount, Bradley, Campbell, Carter and 32 more7 hr
May 21, 6:00 PM CDTMesoscale DiscussionSPCBlount, Claiborne, Cocke, Grainger, Greene, Hamblen and 8 more60 min

Nearby

Mesoscale Discussions in Tennessee, 2013Mesoscale Discussions in Mississippi, 2013Mesoscale Discussions in Arkansas, 2013Every mesoscale discussion in 2013

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.